-Define a national map.
-Define a local map.

The National Map is a collaborative effort of the United States Geological Survey and other federal, state, and local agencies to improve and deliver topographic information for the United States.

A local map is a transform that provides a hierarchical view of element transforms in a message map. You can use local maps to break up a large map into nested groups of mapping elements and process the complex elements of the whole data object. Local maps are a partial view of a larger map, rather than separate files.

Explanation:

because the two particles have an equal charge, the charges will cancel out and give the atom an overall charge of 0. so, if at atom has 35 protons in the nucleus, we could expect it to have 35 electrons orbiting that nucleus.